在Java中沒有輸出

Question

我正在學習Java，我正在嘗試創建一個類並將其實例化。但是當我在Eclipse中執行下面的代碼時，我沒有得到任何輸出。

package day1;

class student { 
    int mark1 = 0; 
    int mark2 = 0; 
    int mark3 = 0; 
    int total = 0; 

    void bio(int newmark) { 
     mark1 = mark1 + newmark; 

    } 

    void chemistry(int newmark) { 
     mark2 = mark2 + newmark; 

    } 

    void maths(int newmark) { 
     mark3 = mark3 + newmark; 

    } 

    void printmarks() { 
     System.out.println(mark1 + mark2 + mark3); 

    } 
} 

public class May24 { 

    public static void main(String[] args) { 

     student student1 = new student(); 
     student student2 = new student(); 
     student1.bio(10); 
     student1.chemistry(20); 
     student1.maths(30); 

     student2.bio(40); 
     student2.chemistry(30); 
     student2.maths(40); 
    } 

} 

有人可以指出我錯在哪裏。謝謝。

Answer 1

因爲不管你做了什麼，只是給類數據成員賦值，你還沒有打電話printmarks()來打印輸出。 加上下面幾行到主（）

student1.printmarks(); 
student2.printmarks(); 

Answer 2

public static void main(String[] args) { 

     student student1 = new student(); 
     student student2 = new student(); 
     student1.bio(10); 
     student1.chemistry(20); 
     student1.maths(30); 
     student1.printmarks(); 

     student2.bio(40); 
     student2.chemistry(30); 
     student2.maths(40); 
     student2.printmarks(); 

    }